using System;

/**
* The Comma Separated Value (CSV) File Format: http://www.creativyst.com/Doc/Articles/CSV/CSV01.htm
* 描述：解析 CSV 格式的文件。
* 由这里 http://blog.csdn.net/emu/archive/2003/03/01/16338.aspx 的Java代码改写而来（增加了行处理）
* 日期： 2004-10-22 14:55
*/
namespace Mitumori {
/// <summary>
/// CSVUtil 用来处理CSV格式的文件内容成一二维数组。
/// </summary>
public class CSVUtil {
private CSVUtil() {
}

/// <summary>
/// 分割 CVS 文件内容为一个二维数组。
/// </summary>
/// <param name="src">CVS 文件内容字符串</param>
/// <returns>二维数组。String[line count][column count]</returns>
public static String[][] SplitCSV(String src) {
// 如果输入为空，返回 0 长度字符串数组
if (src==null || src.Length == 0) return new String[0][]{};
String st="";
System.Collections.ArrayList lines = new System.Collections.ArrayList(); // 行集合。其元素为行
System.Collections.ArrayList cells = new System.Collections.ArrayList(); // 单元格集合。其元素为一个单元格
bool beginWithQuote = false;
int maxColumns = 0;
// 遍历字符串的字符
for (int i=0;i<src.Length;i++){
char ch = src[i];

#region CR 或者 LF
//A record separator may consist of a line feed (ASCII/LF=0x0A),
//or a carriage return and line feed pair (ASCII/CRLF=0x0D 0x0A).
// 这里我不明白CR为什么不作为separator呢，在Mac OS上好像是用CR的吧。
// 这里我“容错”一下，CRLF、LFCR、CR、LF都作为separator
if (ch == '\r') {
#region CR
if (beginWithQuote) {
st += ch;
}
else {
if(i+1 < src.Length && src[i+1] == '\n') { // 如果紧接的是LF，那么直接把LF吃掉
i++;
}

//line = new String[cells.Count];
//System.Array.Copy (cells.ToArray(typeof(String)), line, line.Length);
//lines.Add(line); // 把上一行放到行集合中去

cells.Add(st);
st = "";
beginWithQuote = false;

maxColumns = (cells.Count > maxColumns ? cells.Count : maxColumns);
lines.Add(cells);
st = "";
cells = new System.Collections.ArrayList();
}
#endregion CR
}
else if (ch == '\n') {
#region LF
if (beginWithQuote) {
st += ch;
}
else {
if(i+1 < src.Length && src[i+1] == '\r') { // 如果紧接的是LF，那么直接把LF吃掉
i++;
}

//line = new String[cells.Count];
//System.Array.Copy (cells.ToArray(typeof(String)), line, line.Length);
//lines.Add(line); // 把上一行放到行集合中去

cells.Add(st);
st = "";
beginWithQuote = false;

maxColumns = (cells.Count > maxColumns ? cells.Count : maxColumns);
lines.Add(cells);
st = "";
cells = new System.Collections.ArrayList();
}
#endregion LF
}
#endregion CR 或者 LF
else if (ch == '\"'){ // 双引号
#region 双引号
if (beginWithQuote){
i++;
if (i>=src.Length){
cells.Add(st);
st="";
beginWithQuote=false;
}
else{
ch=src[i];
if (ch == '\"'){
st += ch;
}
else if (ch == ','){
cells.Add(st);
st="";
beginWithQuote = false;
}
else{
throw new Exception("Single double-quote char mustn't exist in filed "+(cells.Count+1)+" while it is begined with quote\nchar at:"+i);
}
}
}
else if (st.Length==0){
beginWithQuote = true;
}
else{
throw new Exception("Quote cannot exist in a filed which doesn't begin with quote!\nfield:"+(cells.Count+1));
}
#endregi